'NoneType' object has no attribute 'attrs' when upgrading to 2.0.0

[rixx]

I just tried upgrading my project to django-bootstrap 2.0.0, and encountered the following error when loading websites.

Traceback (most recent call last):
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/core/handlers/base.py", line 145, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/core/handlers/base.py", line 143, in _get_response
    response = response.render()
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/response.py", line 105, in render
    self.content = self.rendered_content
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/response.py", line 83, in rendered_content
    return template.render(context, self._request)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/backends/django.py", line 61, in render
    return self.template.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 171, in render
    return self._render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/test/utils.py", line 95, in instrumented_test_render
    return self.nodelist.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 936, in render
    bit = node.render_annotated(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 903, in render_annotated
    return self.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/test/utils.py", line 95, in instrumented_test_render
    return self.nodelist.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 936, in render
    bit = node.render_annotated(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 903, in render_annotated
    return self.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/loader_tags.py", line 150, in render
    return compiled_parent._render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/test/utils.py", line 95, in instrumented_test_render
    return self.nodelist.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 936, in render
    bit = node.render_annotated(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 903, in render_annotated
    return self.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/loader_tags.py", line 62, in render
    result = block.nodelist.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 936, in render
    bit = node.render_annotated(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 903, in render_annotated
    return self.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/loader_tags.py", line 62, in render
    result = block.nodelist.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 936, in render
    bit = node.render_annotated(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/base.py", line 903, in render_annotated
    return self.render(context)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/django/template/library.py", line 192, in render
    output = self.func(*resolved_args, **resolved_kwargs)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/bootstrap4/templatetags/bootstrap4.py", line 627, in bootstrap_field
    return render_field(*args, **kwargs)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/bootstrap4/forms.py", line 39, in render_field
    return renderer_cls(field, **kwargs).render()
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/bootstrap4/renderers.py", line 84, in render
    return mark_safe(self._render())
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/bootstrap4/renderers.py", line 515, in _render
    html = self.post_widget_render(html)
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/bootstrap4/renderers.py", line 363, in post_widget_render
    html = self.list_to_class(html, "checkbox")
  File "/home/rixx/.local/share/virtualenvs/pretalx/lib/python3.8/site-packages/bootstrap4/renderers.py", line 341, in list_to_class
    label.input.attrs["class"] = label.input.attrs.get("class", []) + ["form-check-input"]
AttributeError: 'NoneType' object has no attribute 'attrs'

This is a direct regression to #181, where django-bootstrap4 assumes that all inputs have to be inside labels (which is not idiomatic or at least not required in HTML).

[dyve]

Thanks. Apparently there is no test on this regression. Will look into that.

The major version dump in 2 is because of the drop n support fro Python and Django versions. You should be fine with django-bootstrap4<2.

[dyve]

Is there any chance you can provide a breaking test? In v1.1.1 we fixed it based on symptoms, but a breaking test would be much better.

Copy/paste here is fine if you do not want to do a PR.